JP2615114B2 - Manufacturing method of multilayer ceramic capacitor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer ceramic capacitor that prevents a phenomenon (delamination) between an electrode and a dielectric caused by a conductive paste.

[Prior art] Conventionally, a multilayer ceramic capacitor is manufactured through a ceramic green sheet forming process, an internal electrode pattern printing process, a capacitor chip cutting process, a binder burning process, a firing process, an external electrode baking process, and the like. In the pattern printing step, an electrode pattern is formed by printing on a ceramic green sheet using a conductive paste, and a green chip is obtained. As the conductive paste, palladium (Pd) alone or a mixture of metal powder obtained by pulverizing both palladium (Pd) and platinum (Ag) into fine particles and a binder made of an organic substance is used.

The green chip adheres to the ceramic green sheet by the adhesiveness of the binder in the internal electrode paste to form a desired electrode pattern. However, the binder on the green chip is removed by burning during a binder burning step or firing step, and the electrode pattern has a final shape due to sintering of the ceramic powder and the metal powder.

[Problems to be solved by the invention]

By the way, in the binder baking step, a rapid exothermic reaction is caused by the catalytic action of palladium contained in the conductive paste, and the generated heat becomes a high temperature far exceeding the temperature required for burning the binder. It is known that when such a high temperature is used between the ceramic green sheet and the conductive paste, delamination occurs between the electrode formed by combustion and the ceramic green sheet.

That is, in sintering the ceramic powder and the metal powder, the metal powder sinters at a lower temperature than the ceramic powder, and there is a temperature difference between the two in sintering. Such a temperature difference appears as a difference in sintering shrinkage between the two, and this causes internal stress due to sintering shrinkage of the metal powder, which causes delamination.

In addition, it is assumed that the ceramic powder and the metal powder are in contact with each other before sintering.However, rapid combustion of the binder during the binder burning process and rapid scattering of the gasified binder to the outside of the chip are caused by the ceramic and metal. Cracks, which reduce the point of contact between the ceramic and the metal, causing delamination.

Accordingly, it is an object of the present invention to suppress the occurrence of delamination by suppressing an abnormal rise in temperature due to a catalytic action of a binder in a conductive paste during combustion.

[Means for solving the problem]

The method for manufacturing the multilayer ceramic capacitor of the present invention includes:
It is characterized in that a conductive paste containing a chlorine-based flame retardant is used for forming the internal electrodes.

[Action]

If a chlorine-based flame retardant is added to the conductive paste, the combustion is moderated against the rapid exothermic reaction caused by the catalytic action of metal powder such as palladium contained in the conductive paste, and the temperature rises sharply to an abnormal temperature. It is possible to suppress.

In the method for manufacturing a multilayer ceramic capacitor of the present invention, the chlorine-based flame retardant may be a conductive paste if any of paraffin chloride, tetrachlorophthalic anhydride, polyethylene chloride, hexachloroendmethylenetetrahydrophthalic acid, and perchloropentacyclodecane is used. In response to a rapid exothermic reaction caused by the catalytic action of a metal powder such as palladium contained therein, the combustion is moderated to prevent a rapid temperature rise and temperature rise, thereby suppressing delamination.

〔Example〕

Hereinafter, embodiments of the method for manufacturing a multilayer ceramic capacitor according to the present invention will be described.

It is the same as the conventional manufacturing method that the multilayer ceramic capacitor is manufactured through a ceramic green sheet forming process, an internal electrode pattern printing process, a capacitor chip cutting process, a binder burning process, a firing process, and a baking process of an external electrode. However, the present invention is characterized in that in the internal electrode pattern printing step, the internal electrode pattern is formed using a conductive paste to which a chlorine-based flame retardant has been added. As the chlorine-based flame retardant added to the conductive paste, paraffin chloride, tetrachlorophthalic anhydride, polyethylene chloride, hexachloroendmethylenetetrafudrophthalic acid, perchloropentacyclodecane, or the like is used.

Table 1 shows a composition example of the conductive paste. Example 1
No. 5 is a comparative example having a basic composition in which a chlorine-based flame retardant was selected and mixed with 1 part by weight.

In the internal electrode pattern printing step, an internal electrode pattern was printed on a ceramic green sheet formed in advance using the conductive pastes of Comparative Examples in Table 1 and Examples 1 to 5.

Next, in the cutting step, the ceramic green sheet on which the internal electrode pattern is printed is cut into predetermined sections to obtain green chips.

Next, in the binder burning step, the green chips are heated to burn the binder in the conductive paste forming the electrode pattern. In this case, a temperature step of 1 ° C / min
The temperature is raised to 0-250 ° C. and the temperature is maintained for several hours to burn the binder.

In the combustion of such a binder, the chlorine-based flame retardant mixed into the conductive paste moderates the catalytic action of the metal powder in the basic composition and suppresses a rapid exothermic reaction.

Next, firing is performed in a firing step, and then external electrodes are fired to obtain a multilayer ceramic capacitor.

Table 2 shows the number of occurrences of delamination corresponding to the conductive pastes shown in Table 1 for the multilayer ceramic capacitors obtained through such a manufacturing process.

As for the prototype capacitors of the comparative example and Examples 1 to 5, ten external capacitors each having a size of 2 mm × 1.2 mm (thickness differs depending on the number of layers) were prepared for each sample, and the occurrence of delamination was examined. Things.

As is clear from the results in Table 2, the capacitors of Examples 1 to 5 using the conductive paste containing a chlorine-based flame retardant had a large number of delaminations of the capacitor of the comparative example including only the basic composition. It can be seen that no or very little delamination occurs. That is, in the combustion of the binder, the chlorine-based flame retardant mixed in the conductive paste moderates the catalytic action of the metal powder in the basic composition, suppresses a rapid exothermic reaction, and suppresses the occurrence of delamination. It turns out that there is.

In Examples, chlorinated paraffin,
One of tetrachlorophthalic anhydride, polyethylene chloride, hexachloroendomethylenetetrahydrophthalic acid, perchloropentacyclodecane, etc. was selected and used.
Two or more may be selected and mixed into the conductive paste.

〔The invention's effect〕

As described above, according to the present invention, since the conductive paste containing the chlorine-based flame retardant is used, the rapid exothermic reaction of the catalytic action of the binder in the binder firing step can be mitigated, and the occurrence of delamination is suppressed. can do.

If the chlorine-based flame retardant is paraffin chloride, tetrachlorophthalic anhydride, polyethylene chloride, hexachloroendmethylenetetrahydrophthalic acid, perchloropentacyclodecane, etc., the rapid exothermic reaction of the binder can be effectively suppressed. As a result, it is possible to prevent the occurrence of delamination and to manufacture a multilayer ceramic capacitor having excellent characteristics.

Claims (2)

(57) [Claims] 1. A method for manufacturing a multilayer ceramic capacitor, wherein a conductive paste containing a chlorine-based flame retardant is used for forming internal electrodes. 2. The chlorine-based flame retardant according to claim 1, wherein any one of paraffin chloride, tetrachlorophthalic anhydride, polyethylene chloride, hexachloroendmethylenetetrahydrophthalic acid, and perchloropentacyclodecane is used. A manufacturing method of the multilayer ceramic capacitor according to the above.